Examination of surface contamination and impurities in tinplate samples, both passivated and non-passivated

Abstract

This study examined the surfaces of non-passivated and passivated tinplate samples, as well as the impurities present on them, using SEM, EDS, and GDOES. Additionally, solutions were analyzed using ICP in order to identify any correlations between the elements present in the solutions and on the strip surfaces. The results from GDOES indicated the presence of unwanted elements, such as Sn, S, Cr, N, P, Zn, Fe, Mn, C, and Si, on both the passivated and non-passivated sample surfaces. SEM analysis of the passivated sample revealed light and dark regions in parallel lines, which were observed ahead of the rolling direction. EDS analysis indicated that the light areas were rich in Sn while the dark areas were rich in Fe, and C was identified as an unwanted element in both areas. O and Cr were only found in the dark areas. EDS analysis of the impurities revealed Na, S, Cl, Ca, Mg, Si, N, and Al as unwanted elements. The results suggest that unwanted elements are transferred from the steel strip surface to different solutions in the tinplate line, causing pollution in various solutions.